.\"
.\" SPDX-License-Identifier: ISC
.\"
.\" Copyright (c) 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd November 24, 2020
.Dt SUDO_LOGSRVD.CONF @mansectform@
.Os Sudo @PACKAGE_VERSION@
.Sh NAME
.Nm sudo_logsrvd.conf
.Nd configuration for sudo_logsrvd
.Sh DESCRIPTION
The
.Nm sudo_logsrvd.conf
file is used to configure the
.Nm sudo_logsrvd
log server.
It uses an INI-style format made up of sections in square brackets and
.Dq key = value
pairs specific to each section below the section name.
Depending on the key, values may be integers, booleans or strings.
Section and key names are not case sensitive, but values are.
.Pp
The pound sign
.Pq Ql #
is used to indicate a comment.
Both the comment character and any text after it, up to the end of
the line, are ignored.
Lines beginning with a semi-colon
.Pq Ql \&;
are also ignored.
.Pp
Long lines can be continued with a backslash
.Pq Ql \e
as the last character on the line.
Note that leading white space is removed from the beginning of lines
even when the continuation character is used.
.Pp
The
.Sx EXAMPLES
section contains a copy of the default
.Nm
file.
.Pp
The following configuration sections are recognized:
.Pp
.Bl -bullet -compact -offset indent
.It
server
.It
iolog
.It
eventlog
.It
syslog
.It
logfile
.El
.Pp
Each section is described in detail below.
.Ss server
The
.Em server
section configures the address and port the server will listen on.
The following keys are recognized:
.Bl -tag -width 8n
.It listen_address = host Ns Oo : Ns port Oc Ns Op (tls)
The host name or IP address, optional port to listen on and
an optional Transport Layer Security (TLS) flag in parentheses.
.Pp
The host may be a host name, an IPv4 address, an IPv6 address
in square brackets or the wild card entry
.Ql * .
A host setting of
.Ql *
will cause
.Nm sudo_logsrvd
to listen on all configured network interfaces.
.Pp
If the optional tls flag is present,
.Nm sudo_logsrvd
will secure the connection with TLS version 1.2 or 1.3.
Versions of TLS prior to 1.2 are not supported.
See
.Xr sudo_logsrvd @mansectsu@
for details on generating TLS keys and certificates.
.Pp
If a port is specified, it may either be a port number or a known
service name as defined by the system service name database.
If no port is specified, port 30343 will be used for plaintext
connections and port 30344 will be used for TLS connections.
.Pp
The default value is:
.Bd -literal -compact -offset indent
listen_address = *:30343
listen_address = *:30344(tls)
.Ed
which will listen on all configured network interfaces for both
plaintext and TLS connections.
Multiple
.Em listen_address
lines may be specified to listen on more than one port or interface.
.It pid_file = path
The path to the file containing the process ID of the running
.Nm sudo_logsrvd .
If set to an empty value, or if
.Nm sudo_logsrvd
is run with the
.Fl n
option, no
.Em pid_file
will be created.
If
.Em pid_file
refers to a symbolic link, it will be ignored.
The default value is
.Pa @rundir@/sudo_logsrvd.pid .
.It tcp_keepalive = boolean
If true,
.Nm sudo_logsrvd
will enable the TCP keepalive socket option on the client connection.
This enables the periodic transmission of keepalive messages to the client.
If the client does not respond to a message, the connection will be closed.
.It timeout = number
The amount of time, in seconds,
.Nm sudo_logsrvd
will wait for the client to respond.
A value of 0 will disable the timeout.
The default value is 30.
.It tls_cacert = path
The path to a certificate authority bundle file, in PEM format,
to use instead of the system's default certificate authority database
when authenticating clients.
The default is to use
.Pa /etc/ssl/sudo/cacert.pem
if it exists, otherwise the system's default certificate authority
database is used.
.It tls_cert = path
The path to the server's certificate file, in PEM format.
The default value is
.Pa /etc/ssl/sudo/certs/logsrvd_cert.pem .
.It tls_checkpeer = bool
If true, client certificates will be validated by the server;
clients without a valid certificate will be unable to connect.
If false, no validation of client certificates will be performed.
It true and client certificates are created using a private certificate
authority, the
.Em tls_cacert
setting must be set to a CA bundle that contains the CA certificate
used to generate the client certificate.
The default value is
.Li false .
.It tls_ciphers_v12 = string
A list of ciphers to use for connections secured by TLS version 1.2 only,
separated by a colon
.Ql :\& .
See the
.Sx CIPHER LIST FORMAT
section in
.Xr openssl-ciphers 1
for full details.
The default value is
.Li HIGH:!aNULL
which consists of encryption cipher suites with key lengths larger than
128 bits, and some cipher suites with 128-bit keys.
Cipher suites that offer no authentication are excluded.
.It tls_ciphers_v13 = string
A list of ciphers to use for connections secured by TLS version 1.3 only,
separated by a colon
.Ql :\& .
Supported cipher suites depend on the version of OpenSSL used,
but should include the following:
.Pp
.Bl -tag -compact -width 8n -offset indent
.It TLS_AES_128_GCM_SHA256
.It TLS_AES_256_GCM_SHA384
.It TLS_CHACHA20_POLY1305_SHA256
.It TLS_AES_128_CCM_SHA256
.It TLS_AES_128_CCM_8_SHA256
.El
.Pp
The default cipher suite is TLS_AES_256_GCM_SHA384.
.It tls_dhparams = path
The path to a file containing custom Diffie-Hellman parameters in PEM format.
This file can be created with the following command:
.Bd -literal
openssl dhparam -out /etc/sudo_logsrvd_dhparams.pem 2048
.Ed
.Pp
By default,
.Nm sudo_logsrvd
will use the OpenSSL defaults for Diffie-Hellman key generation.
.It tls_key = path
The path to the server's private key file, in PEM format.
The default value is
.Pa /etc/ssl/sudo/private/logsrvd_key.pem .
.It tls_verify = bool
If true, the server certificate will be verified at startup and
clients will authenticate the server by verifying its certificate
and identity.
If false, no verification is performed of the server certificate
by the server or the client.
When using self-signed certificates without a certificate authority,
this setting should be set to false.
The default value is true.
.El
.Ss iolog
The
.Em iolog
section configures I/O log parameters.
These settings are identical to the I/O configuration in
.Xr sudoers @mansectform@ .
The following keys are recognized:
.Bl -tag -width 8n
.It iolog_compress = boolean
If set, I/O logs will be compressed using
.Sy zlib .
Enabling compression can make it harder to view the logs in real-time as
the program is executing due to buffering.
The default value is
.Li false .
.It iolog_dir = path
The top-level directory to use when constructing the path
name for the I/O log directory.
The session sequence number, if any, is stored in the directory.
The default value is
.Pa @iolog_dir@ .
.Pp
The following percent
.Pq Ql %
escape sequences are supported:
.Bl -tag -width 4n
.It Li %{seq}
expanded to a monotonically increasing base-36 sequence number, such as 0100A5,
where every two digits are used to form a new directory, e.g.,
.Pa 01/00/A5
.It Li %{user}
expanded to the invoking user's login name
.It Li %{group}
expanded to the name of the invoking user's real group-ID
.It Li %{runas_user}
expanded to the login name of the user the command will
be run as (e.g., root)
.It Li %{runas_group}
expanded to the group name of the user the command will
be run as (e.g., wheel)
.It Li %{hostname}
expanded to the local host name without the domain name
.It Li %{command}
expanded to the base name of the command being run
.El
.Pp
In addition, any escape sequences supported by the system's
.Xr strftime 3
function will be expanded.
.Pp
To include a literal
.Ql %
character, the string
.Ql %%
should be used.
.It iolog_file = path
The path name, relative to
.Em iolog_dir ,
in which to store I/O logs.
Note that
.Em iolog_file
may contain directory components.
The default value is
.Li %{seq} .
.Pp
See the
.Em iolog_dir
setting above for a list of supported percent
.Pq Ql %
escape sequences.
.Pp
In addition to the escape sequences, path names that end in six or
more
.Li X Ns s
will have the
.Li X Ns s
replaced with a unique combination of digits and letters, similar to the
.Xr mktemp 3
function.
.Pp
If the path created by concatenating
.Em iolog_dir
and
.Em iolog_file
already exists, the existing I/O log file will be truncated and
overwritten unless
.Em iolog_file
ends in six or
more
.Li X Ns s .
.It iolog_flush = boolean
If set, I/O log data is flushed to disk after each write instead of
buffering it.
This makes it possible to view the logs in real-time as the program is
executing but may significantly reduce the effectiveness
of I/O log compression.
The default value is
.Li true .
.It iolog_group = name
The group name to look up when setting the group-ID on new I/O log
files and directories.
If
.Em iolog_group
is not set,
the primary group-ID of the user specified by
.Em iolog_user is used.
If neither
.Em iolog_group
nor
.Em iolog_user
are set, I/O log files and directories are created with group-ID 0.
.It iolog_mode = mode
The file mode to use when creating I/O log files.
Mode bits for read and write permissions for owner, group or other
are honored, everything else is ignored.
The file permissions will always include the owner read and
write bits, even if they are not present in the specified mode.
When creating I/O log directories, search (execute) bits are added
to match the read and write bits specified by
.Em iolog_mode .
The default value is
.Li 0600 .
.It iolog_user = name
The user name to look up when setting the owner of new
I/O log files and directories.
If
.Em iolog_group
is set, it will be used instead of the user's primary group-ID.
By default, I/O log files and directories are created with user and
group-ID 0.
.It maxseq = number
The maximum sequence number that will be substituted for the
.Dq Li %{seq}
escape in the I/O log file (see the
.Em iolog_dir
description above for more information).
While the value substituted for
.Dq Li %{seq}
is in base 36,
.Em maxseq
itself should be expressed in decimal.
Values larger than 2176782336 (which corresponds to the
base 36 sequence number
.Dq ZZZZZZ )
will be silently truncated to 2176782336.
The default value is 2176782336.
.El
.Ss eventlog
The
.Em eventlog
section configures how (and if) security policy events are logged.
.Bl -tag -width 4n
.It log_type = string
Where to log accept, reject and alert events reported by the policy.
Supported values are
.Em syslog ,
.Em logfile ,
and
.Em none .
The default value is
.Em syslog .
.It log_format = string
The event log format.
Supported log formats are
.Dq sudo
for traditional sudo-style logs and
.Dq json
for JSON-format logs.
The JSON log entries contain the full contents of the accept, reject
and alert messages.
The default value is
.Em sudo .
.El
.Ss syslog
The
.Em syslog
section configures how events are logged via
.Xr syslog 3 .
.Bl -tag -width 4n
.It facility = string
Syslog facility if syslog is being used for logging.
Defaults to
.Li @logfac@ .
.Pp
The following syslog facilities are supported:
.Sy authpriv
(if your
OS supports it),
.Sy auth ,
.Sy daemon ,
.Sy user ,
.Sy local0 ,
.Sy local1 ,
.Sy local2 ,
.Sy local3 ,
.Sy local4 ,
.Sy local5 ,
.Sy local6 ,
and
.Sy local7 .
.It accept_priority = string
Syslog priority to use when the user is allowed to run a command and
authentication is successful.
Defaults to
.Li @goodpri@ .
.Pp
The following syslog priorities are supported:
.Sy alert ,
.Sy crit ,
.Sy debug ,
.Sy emerg ,
.Sy err ,
.Sy info ,
.Sy notice ,
.Sy warning ,
and
.Sy none .
Setting it to a value of
.Sy none
will disable logging of successful commands.
.It reject_priority = string
Syslog priority to use when the user is not allowed to run a command or
when authentication is unsuccessful.
Defaults to
.Li @badpri@ .
.Pp
See
.Em accept_priority
for the list of supported syslog priorities.
.It alert_priority = string
Syslog priority to use for event log alert messages received from the client.
Defaults to
.Li @badpri@ .
.Pp
See
.Em accept_priority
for the list of supported syslog priorities.
.It maxlen = number
On many systems,
.Xr syslog 3
has a relatively small log buffer.
IETF RFC 5424 states that syslog servers must support messages of
at least 480 bytes and should support messages up to 2048 bytes.
By default,
.Nm sudo_logsrvd
creates log messages up to 960 bytes which corresponds to the
historic
.Bx
syslog implementation which used a 1024 byte buffer
to store the message, date, hostname and program name.
.Pp
To prevent syslog messages from being truncated,
.Nm sudo_logsrvd
will split up sudo-style log messages that are larger than
.Em maxlen
bytes.
When a message is split, additional parts will include the string
.Dq Pq command continued
after the user name and before the continued command line arguments.
JSON-format log entries are never split and are not affected by
.Em maxlen .
.El
.Ss logfile
The
.Em logfile
section consists of settings related to logging to a plain file
(not syslog).
.Bl -tag -width 4n
.It path = string
The path to the file-based event log.
This path must be fully-qualified and start with a
.Sq /
character.
The default value is
.Pa @logpath@ .
.It time_format = string
The string used when formatting the date and time for file-based event logs.
Formatting is performed via the system's
.Xr strftime 3
function so any escape sequences supported by that function will be expanded.
The default value is
.Dq Li "%h %e %T"
which produces dates like
.Dq Oct  3 07:15:24
in the C locale.
.El
.Sh FILES
.Bl -tag -width 24n
.It Pa @sysconfdir@/sudo_logsrvd.conf
Sudo log server configuration file
.El
.Sh EXAMPLES
.Bd -literal
#
# sudo logsrv configuration
#

[server]
# The host name or IP address and port to listen on with an optional TLS
# flag.  If no port is specified, port 30343 will be used for plaintext
# connections and port 30344 will be used to TLS connections.
# The following forms are accepted:
#   listen_address = hostname(tls)
#   listen_address = hostname:port(tls)
#   listen_address = IPv4_address(tls)
#   listen_address = IPv4_address:port(tls)
#   listen_address = [IPv6_address](tls)
#   listen_address = [IPv6_address]:port(tls)
#
# The (tls) suffix should be omitted for plaintext connections.
#
# Multiple listen_address settings may be specified.
# The default is to listen on all addresses.
#listen_address = *:30343
#listen_address = *:30344(tls)

# The file containing the ID of the running sudo_logsrvd process.
#pid_file = @rundir@/sudo_logsrvd.pid

# If set, enable the SO_KEEPALIVE socket option on the connected socket.
#tcp_keepalive = true

# The amount of time, in seconds, the server will wait for the client to
# respond.  A value of 0 will disable the timeout.  The default value is 30.
#timeout = 30

# If set, server certificate will be verified at server startup and
# also connecting clients will perform server authentication by
# verifying the server's certificate and identity.
#tls_verify = true

# Whether to verify client certificates for TLS connections.
# By default client certs are not checked.
#tls_checkpeer = false

# Path to the certificate authority bundle file in PEM format.
# Required if 'tls_verify' or 'tls_checkpeer' is set.
#tls_cacert = /etc/ssl/sudo/cacert.pem

# Path to the server's certificate file in PEM format.
# Required for TLS connections.
#tls_cert = /etc/ssl/sudo/certs/logsrvd_cert.pem

# Path to the server's private key file in PEM format.
# Required for TLS connections.
#tls_key = /etc/ssl/sudo/private/logsrvd_key.pem

# TLS cipher list (see "CIPHER LIST FORMAT" in the openssl-ciphers manual).
# NOTE that this setting is only effective if the negotiated protocol
# is TLS version 1.2.
# The default cipher list is HIGH:!aNULL.
#tls_ciphers_v12 = HIGH:!aNULL

# TLS cipher list if the negotiated protocol is TLS version 1.3.
# The default cipher list is TLS_AES_256_GCM_SHA384.
#tls_ciphers_v13 = TLS_AES_256_GCM_SHA384

# Path to the Diffie-Hellman parameter file in PEM format.
# If not set, the server will use the OpenSSL defaults.
#tls_dhparams = /etc/ssl/sudo/logsrvd_dhparams.pem

[iolog]
# The top-level directory to use when constructing the path name for the
# I/O log directory.  The session sequence number, if any, is stored here.
#iolog_dir = /var/log/sudo-io

# The path name, relative to iolog_dir, in which to store I/O logs.
# Note that iolog_file may contain directory components.
#iolog_file = %{seq}

# If set, I/O logs will be compressed using zlib.  Enabling compression can
# make it harder to view the logs in real-time as the program is executing.
#iolog_compress = false

# If set, I/O log data is flushed to disk after each write instead of
# buffering it.  This makes it possible to view the logs in real-time
# as the program is executing but reduces the effectiveness of compression.
#iolog_flush = true

# The group to use when creating new I/O log files and directories.
# If iolog_group is not set, the primary group-ID of the user specified
# by iolog_user is used.  If neither iolog_group nor iolog_user
# are set, I/O log files and directories are created with group-ID 0.
#iolog_group = wheel

# The user to use when setting the user-ID and group-ID of new I/O
# log files and directories.  If iolog_group is set, it will be used
# instead of the user's primary group-ID.  By default, I/O log files
# and directories are created with user and group-ID 0.
#iolog_user = root

# The file mode to use when creating I/O log files.  The file permissions
# will always include the owner read and write bits, even if they are
# not present in the specified mode.  When creating I/O log directories,
# search (execute) bits are added to match the read and write bits
# specified by iolog_mode.
#iolog_mode = 0600

# The maximum sequence number that will be substituted for the "%{seq}"
# escape in the I/O log file.  While the value substituted for "%{seq}"
# is in base 36, maxseq itself should be expressed in decimal.  Values
# larger than 2176782336 (which corresponds to the base 36 sequence
# number "ZZZZZZ") will be silently truncated to 2176782336.
#maxseq = 2176782336

[eventlog]
# Where to log accept, reject and alert events.
# Accepted values are syslog, logfile, or none.
# Defaults to syslog
#log_type = syslog

# Event log format.
# Currently only sudo-style event logs are supported.
#log_format = sudo

[syslog]
# The maximum length of a syslog payload.
# On many systems, syslog(3) has a relatively small log buffer.
# IETF RFC 5424 states that syslog servers must support messages
# of at least 480 bytes and should support messages up to 2048 bytes.
# Messages larger than this value will be split into multiple messages.
#maxlen = 960

# The syslog facility to use for event log messages.
# The following syslog facilities are supported: authpriv (if your OS
# supports it), auth, daemon, user, local0, local1, local2, local3,
# local4, local5, local6, and local7.
#facility = authpriv

# Syslog priority to use for event log accept messages, when the command
# is allowed by the security policy.  The following syslog priorities are
# supported: alert, crit, debug, emerg, err, info, notice, warning, none.
#accept_priority = notice

# Syslog priority to use for event log reject messages, when the command
# is not allowed by the security policy.
#reject_priority = alert

# Syslog priority to use for event log alert messages reported by the
# client.
#alert_priority = alert

[logfile]
# The path to the file-based event log.
# This path must be fully-qualified and start with a '/' character.
#path = /var/log/sudo

# The format string used when formatting the date and time for
# file-based event logs.  Formatting is performed via strftime(3) so
# any format string supported by that function is allowed.
#time_format = %h %e %T
.Ed
.Sh SEE ALSO
.Xr strftime 3 ,
.Xr sudo.conf @mansectform@ ,
.Xr sudoers @mansectform@ ,
.Xr sudo @mansectsu@ ,
.Xr sudo_logsrvd @mansectsu@
.Sh HISTORY
See the HISTORY file in the
.Nm sudo
distribution (https://www.sudo.ws/history.html) for a brief
history of sudo.
.Sh AUTHORS
Many people have worked on
.Nm sudo
over the years; this version consists of code written primarily by:
.Bd -ragged -offset indent
.An Todd C. Miller
.Ed
.Pp
See the CONTRIBUTORS file in the
.Nm sudo
distribution (https://www.sudo.ws/contributors.html) for an
exhaustive list of people who have contributed to
.Nm sudo .
.Sh BUGS
If you feel you have found a bug in
.Nm sudo ,
please submit a bug report at https://bugzilla.sudo.ws/
.Sh SUPPORT
Limited free support is available via the sudo-users mailing list,
see https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or
search the archives.
.Sh DISCLAIMER
.Nm sudo
is provided
.Dq AS IS
and any express or implied warranties, including, but not limited
to, the implied warranties of merchantability and fitness for a
particular purpose are disclaimed.
See the LICENSE file distributed with
.Nm sudo
or https://www.sudo.ws/license.html for complete details.
